JPH10179818A - Manufacture of titanium-made golf club head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability and flying distance, and besides enhance reverberation characteristics of hitting sound by using for a face part a material composed of alpha plus beta type titanium alloy processed at a specified range of temperatures. SOLUTION: An alpha plus beta type titanium alloy is used at least for a face part of a golf club head. A temp. at the when a process is applied to the alloy sound be in a range from a temp. obtained by subtracting 100 deg.C from a beta transformation temp. to the beta (B) transformation temp. in order to obtain a two-phase mixed structure having an elongated form. Also, to obtain the two-phase mixed structure, preferably a hot process at the pressure rate of 30% or more should be applied. Accordingly, it is possible to produce a titanium-made golf club excellent in mechanical characteristics such as strength and durability, and high in reverberation characteristics of hitting soud in the frequency ranges of 4-6kHz and 8-10kHz at the time hitting a ball, leading to a deep hitting sound with the harmony of the two frequency range sounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a titanium golf club head, and more particularly, to a method for manufacturing a titanium golf club head having excellent hitting sound reverberation.

[0002]

2. Description of the Related Art In recent years, titanium alloys have been used for the heads of metal wood clubs such as drivers.
The reason is that titanium alloy has a high specific strength, so that it is possible to make the head thinner and have a larger capacity, thereby increasing the area of the sweet spot, and as a result, the direction of the hit ball is stabilized. This is because, by increasing the length of the shaft, the shaft can be lengthened, and there is an advantage that the flight distance can be increased.

[0003] Japanese Patent Application Laid-Open No. 63-154186 (hereinafter referred to as
Prior document 1), Japanese Patent Application Laid-Open No. 4-376678 (hereinafter, referred to as
Prior art 2) and Japanese Patent Publication No. Hei 7-98076 (hereinafter, prior art 3) disclose a method of manufacturing a golf club head using various Ti alloys. In Prior Document 1,
A method is disclosed in which a shell-shaped member made of Ti-6wt.% Al-4wt.% V is integrally joined to each other to assemble a hollow head, and a back weight having a specific gravity higher than that of Ti is fixed to the rear inside the head. Have been. Prior Document 2 discloses that Ti
-4.7 wt.% Al-2.9 wt.% V-2.0 wt.% Mo-
A method is disclosed in which a 2.1 wt.% Fe thin plate is formed into a shell-shaped divided part of a club head by pressing, assembled into a head shell by welding, and further subjected to a solution treatment and an aging treatment. Prior Document 3 discloses that Ti-6 wt.% Al-
4wt.% V crown and Ti-6w
A manufacturing method is disclosed in which a face portion and a sole portion made of t.% Al-4wt.% V are assembled into a head shape by welding, and the rigidity of a crown portion is lower than that of a sole portion.

By the way, golf clubs are required to have not only mechanical performance such as directional stability and flight distance, but also performance that appeals to individual sensitivity such as a hitting sound when hitting a ball. Since this sensational preference varies from person to person, various hitting sounds are required in golf clubs. However, these prior art documents 1 to 3 focus only on mechanical properties such as durability and flight distance of a golf club head, and do not mention hitting sound at all. Also, in the Bulletin of the Japan Institute of Metals, vol. 35 (1996) P. 8 (hereinafter referred to as Prior Document 4), as a result of studying the hitting sound of golf clubs, Hoshi et al. The sound is a reverberation sound after hitting a ball, and it is disclosed that the material that characterizes the sound is a material such as wood, stainless steel, and titanium that constitutes a golf club head.

Therefore, conventionally, there is no other way to control the hitting sound of a golf club, except by changing the material of the head portion. By using titanium, mechanical properties such as an increase in flight distance are improved. At the same time, it was impossible to control the hitting sound. That is, as described above, the prior arts disclosed in the prior art documents 1 to 3 have a problem that only mechanical properties such as durability and flight distance of the golf club head are merely improved.

[0006]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of manufacturing a titanium golf club head having excellent hitting sound reverberation by solving the above-mentioned problems of the prior art.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems. As a result, in the golf club head made of titanium, by devising the manufacturing method and controlling the morphology and the like of the metal structure, the mechanical properties such as the durability or the flight distance of the golf club head are improved, and at the same time, We have found that the reverberation of hitting sound can be improved.

The present invention has been made on the basis of the above-mentioned findings, and a method of manufacturing a titanium golf club head according to the present invention provides a method of manufacturing a titanium golf club head by adding (β transformation temperature) to an α + β type titanium alloy. -100 ° C)
By using at least the face portion processed at a temperature lower than the β transformation temperature, the resilience of the hitting sound at 4 to 6 kHz and 8 to 10 kHz is enhanced.

[0009]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a schematic illustration showing a titanium golf club head manufactured by one of the methods of the present invention. In FIG. 1, 1 denotes a face + fossel portion, 2 denotes a sole portion, and 3 denotes a crown portion.

In the method of the present invention, at least the face portion of the golf club head should use an α + β type titanium alloy. The reason is as follows. That is, in the case of α-type titanium other than pure titanium, plastic working is extremely difficult, and it is difficult to form a complex shape such as a golf club head. Pure titanium does not satisfy the strength required for a golf club head, and causes deformation of the head. On the other hand, in the case of β-type titanium, a two-phase mixed structure in an elongated form as described later cannot be obtained, and desired acoustic characteristics cannot be obtained.

The temperature at which the α + β type titanium alloy is processed is as follows:
In order to obtain a two-phase mixed structure in an elongated form, the temperature should be between (β transformation temperature −100 ° C.) and less than the β transformation temperature. If the temperature is less than (β transformation temperature−100 ° C.), plastic working is difficult, and the golf club head cannot be formed into a shape. On the other hand, at a temperature equal to or higher than the β transformation temperature, a two-phase mixed structure in an elongated form cannot be obtained, and desired acoustic characteristics cannot be obtained.

Furthermore, in order to obtain the above-described elongated two-phase mixed structure, it is desirable to perform hot working with a rolling reduction of 30% or more. The biphasic mixed structure in the elongated form thus obtained has the following characteristics. That is,
In addition to having a two-phase mixed structure, both the α phase and the β phase are elongated in a direction perpendicular to the thickness direction. Such a tissue form has the effect of increasing the reverberation of a hitting sound in a frequency band of 8 to 10 kHz. Furthermore, in the above-mentioned α phase, strain is accumulated, and as a result,
This has the effect of increasing the reverberation of a hitting sound in a frequency band of 4 to 6 kHz. Therefore, the above-described expanded form 2
A titanium golf club head manufactured by using an α + β-type titanium alloy having a phase-mixed structure for at least the face portion,
It has excellent hitting sound reverberation in a frequency band of 4 to 6 kHz and a frequency band of 8 to 10 kHz.

The titanium golf club head manufactured by the method of the present invention not only has excellent mechanical properties such as strength and durability, but also has the above-mentioned two frequency bands when hit with a golf ball. It also has a deep reverberation sound, that is, a hitting sound due to harmony.

[0014]

Next, a method for manufacturing a titanium golf club head according to the present invention will be described with reference to examples.

Using titanium alloys A to E having the component compositions A to E shown in Table 1, round bars and sheets of titanium alloy were prepared. Alloys A and B are α-type titanium alloys, alloys C and D are α + β-type titanium alloys, and alloy E is a β-type titanium alloy. Next, a face + fossel portion having a plate thickness of 2.5 to 3.0 mm is prepared from the titanium alloy round bar by hot working at the temperature shown in Table 2, and then, from the titanium alloy plate material Depending on the hot working, 1.0 to
A crown having a thickness of 1.5 mm and 1.5 to
A sole part having a plate thickness of 2.0 mm was prepared.

Each of these parts was air-cooled to room temperature immediately after hot working. The average cooling rate from the temperature immediately after the processing to the temperature of 300 ° C. was 3 to 10 ° C./s depending on the plate thickness. Tables 2 and 3 show the processing conditions and molding results of the face + fosel portion.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

As is clear from Tables 2 and 3, specimen No. 1 using alloy A was used as the face + fosel portion. Specimen No. B1 using Alloy E B3,
Specimen No. No. which was processed at a temperature of (β transformation temperature −100 ° C.) or more using alloy C or D as the face + fuser portion. A1 to A12, A13, A1
4, B6 and B7 could be molded without cracking. On the other hand, the specimen No. Specimen No. B2 which was processed at a temperature lower than (β transformation temperature −100 ° C.) using alloy C or D as the face + fosel portion. In B4 and B5, cracks occurred during molding.

Next, as shown in Tables 2 and 3, each member made of each material was molded with respect to the specimen which could be molded without cracking in the face + fossel portion as described above. After that, the three members were butt-welded by TIG welding to assemble a golf club head. At this time, the volume of the golf club head is about 28
It was 0 cc. Next, the golf club head thus assembled was subjected to the heat treatment shown in Table 4 and then a shaft was attached thereto to prepare a specimen. A durability test was performed on the specimen thus prepared. In the durability test, the golf ball was hit 5000 times at a head speed of 50 m / s, and it was checked whether the head portion was bent or cracked. If the head portion was not bent or cracked, the golf ball passed the test. Those that were bent or cracked were rejected. The specimen No. A1-1 to A1-3 and the specimen No. A7-1 to A7-3 are each a specimen N
o. A1 and the specimen No. A club head assembled using the same material as A7 was subjected to the heat treatment shown in Table 3. Table 4 also shows the results of the durability test.

[0022]

[Table 4]

As is clear from Table 4, the specimen No. A
1 to A12, A1-1 to A1-3, A7-1 to A7-
3, B6 and B7 showed sufficient durability and passed. On the other hand, the specimen No. B1 and B3 were deformed or cracked and failed.

Next, an acoustic test was performed on the test piece of the golf club that passed the durability test described above by the following test method. That is, first, a golf ball was hit at a head speed of 45 m / s, and the hitting sound was recorded on a data recorder. Next, this was reproduced and subjected to frequency analysis using an FFT analyzer. At this time, the frequency band is 4 to 6
kHz, 6 to 8 kHz, and 8 to 10 kHz, and the time required for the sound pressure in each band to attenuate to 60 dB was measured and defined as the reverberation time. Table 5 shows the results. In Table 5, a reverberation time of 30 ms or more is indicated by a circle, and a reverberation time less than 30 ms is indicated by a cross.

Further, after the completion of the acoustic test, the microstructure observation and the hardness test of the face cross section were performed. Table 4 also shows the results. In Table 5, the aspect ratio indicates a value obtained by dividing the average crystal grain size in the face extension direction by the average crystal grain size in the plate thickness direction. Hardness (Vickers hardness: HV,
The unit is 10 kgf), which is the average of the measured values at five points at the center of the thickness of the surface of the structure observation surface.

[0026]

[Table 5]

As is clear from Table 5, the specimen N of the present invention
o. In A1 to A12, the hitting sound reverberation in the frequency band of 4 to 6 kHz and the frequency band of 8 to 10 kHz was high. On the other hand, the comparative specimen No. having a slow cooling rate after processing. A13, A14, and comparative specimen No. No. A1-1, A7-1
Had a low hitting sound reverberation in the frequency band of 4 to 6 kHz due to the release of the distortion. Further, the comparative specimen No. having an aspect ratio of less than 3 was used. A1-
2, 4 to 6 in A1-3, A7-2, and A7-3
Both the hitting sound reverberation in the frequency band of kHz and the frequency band of 8 to 10 kHz were low.

[0028]

According to the method of the present invention, not only are the mechanical properties such as strength and durability excellent, but also the frequency band of 4 to 6 kHz and 8 to 10 kHz when hitting a golf ball.
The method of manufacturing a titanium golf club head having high hitting sound in the frequency band of z and having a deep hitting sound due to harmony of the sounds in these two frequency bands can be provided, which is an industrially useful effect. Is brought.

[Brief description of the drawings]

FIG. 1 is a schematic illustration showing a titanium golf club head manufactured by one of the methods of the present invention.

[Explanation of symbols]

 1. Face + Fossel 2. Sole 3. Crown

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C22F 1/00 683 C22F 1/00 683 694 694B

Claims (1)

[Claims] In the manufacture of a titanium golf club head, an α + β type titanium alloy processed at a temperature between (β transformation temperature −100 ° C.) and less than a β transformation temperature is used for at least the face portion. A method of manufacturing a golf club head made of titanium, characterized by enhancing the reverberation of a hitting sound at 4 to 6 kHz and 8 to 10 kHz.